> it's just that the databases are disjoint and thus even more error prone because they're run individually by states.
That is a huge advantadge if the federal governments ever gets taken over by totalitarians. Surely at least some states will refuse to authenticate their ID cards when requested by the feds, some may even issue fake IDs to resistance members. If the feds have a centralized database with updated information on residences etc, they can quietly disappear people.
Driving policy decisions based on this fanfic seems like a poor move. The federal government already has several centralized databases of residences (to pick a boring one: income tax forms).